程序来找到系列4、14、28、46、68、94、124、158，…的Nth项。

给定数字N。任务是编写一个程序来查找以下系列的第N个术语：

4, 14, 28, 46, 68, 94, 124, 158…..(N Terms)

例子：

Input: N = 4
Output: 46
For N = 4
4th Term = ( 2 * 4 * 4 + 4 * 4 - 2) 
         = 46

Input: N = 10
Output: 237

方法：本系列的广义第N个术语：

$nth\: Term\: of\: the\: series\: = 2*n^2+4*n-2$

以下是所需的实现：

C++

// CPP program to find the N-th term of the series:
// 4, 14, 28, 46, 68, 94, 124, 158, .....
#include 
#include 
using namespace std;
 
// calculate Nth term of series
int nthTerm(int n)
{
    return 2 * pow(n, 2) + 4 * n - 2;
}
 
// Driver code
int main()
{
    int N = 4;
 
    cout << nthTerm(N) << endl;
 
    return 0;
}

Java

// Java program to find the N-th term of the series:
// 4, 14, 28, 46, 68, 94, 124, 158, .....
import java.util.*;
 
class solution
{
  
// calculate Nth term of series
static int nthTerm(int n)
{
 
    return 2 *(int)Math.pow(n, 2) + 4 * n - 2;
 
}
 
//Driver code
public static void main(String arr[])
{
    int N = 4;
 
   System.out.println(nthTerm(N));
}
}
 
//This code is contributed by Surendra_Gangwar

Python3

# Python3 program to find the
# N-th term of the series:
# 4, 14, 28, 46, 68, 94, 124, 158, .....
 
# calculate Nth term of series
def nthTerm(n):
 
    return 2 * pow(n, 2) + 4 * n - 2
 
# Driver code
N = 4
print(nthTerm(N))
 
# This code is contributed by
# Sanjit_Prasad

C#

// C# program to find the
// N-th term of the series:
// 4, 14, 28, 46, 68, 94, 124, 158, .....
using System;
 
class GFG
{
 
// calculate Nth term of series
static int nthTerm(int n)
{
    return 2 * (int)Math.Pow(n, 2) +
                             4 * n - 2;
}
 
// Driver Code
public static void Main()
{
    int N = 4;
    Console.Write(nthTerm(N));
}
}
 
// This code is contributed
// by Sanjit_Prasad

Javascript

// JavaScript program to find the N-th term of the series:
// 4, 14, 28, 46, 68, 94, 124, 158, .....
 
// calculate Nth term of series
function nthTerm( n)
{
    return 2 * Math.pow(n, 2) + 4 * n - 2;
}
 
// Driver code
let N = 4;
 
   document.write( nthTerm(N) );
 
// This code contributed by gauravrajput1
 

输出：

46

时间复杂度： O(1)